Today, I walked into K-Mart and purchased three pairs of jeans. All three were tagged with the same size, description and price. The only difference visually was the colour of the material used for each one. When I got them home however, I discovered that one fitted me perfectly, one was extra tight around the legs and wouldn't go around my waist, making it impossible to button up, let alone zip the fly up, and the other one was fine in the leg area but also wouldn't fit around my waist. All of the trousers I already own are this size and fit perfectly.
The Mrs. also purchased some tops while she was there today and knows that sizes are never consistent from one brand to the next. She tried on some tops based on how they looked when she held them up in front of her to guestimate the actual size first. Of the tops she was looking at, there were three size 18s and 2 size 22s. One of the 22s was too small, while the other fitted perfectly, as did two of the 18s, yet the third 18 was too big.
I read online a while ago that there are currently no standards or regulations when it comes to clothing sizes in Australia, and clothing manufacturers are free to add whatever size number they like to their products. It's the same with shoes, jackets, trousers, shirts, etc. So while some brands try to have an unofficial standard set of sizes to stick to, others deliberately set sizes to be larger than what they really are, which usually means it costs more to purchase because the size number makes it a plus size, even if it isn't really as big as they claim, while other brands set sizes to be smaller than what they really are in order to make the customer think they're wearing something smaller, because some people like to think they've lost a size or two, so naturally they'll choose something that says they've gone down a size if the "smaller" choice fits. Unfortunately, sometimes the only thing that is smaller is the size number itself.
It would be nice if there was a national standard for all clothing sizes in Australia that clothing manufacturers were required to adhere to when adding sizing labels to their products. It's very difficult to find clothes that fit nowadays no matter what the label says on the things.